The present invention relates to the field of custom part making, and particularly to automated or computer assisted communication and manufacture regarding custom parts. More specifically, the present invention relates to software supported methods, systems and tools used in the design and fabrication of custom parts to be formed with tapped holes for receiving a threaded fastener, and in presenting information to customers for the customer to have selective computer-assisted smart input into the design and quotation of parts with tapped holes.
As in many other areas of industry, various computer advances have been applied to custom part manufacturing. Today, most part designers do not prepare part drawings by hand, but rather prepare part drawings through commercially available programs referred to as CAD (Computer-Aided Design) software. Also, in many situations, machining operations are not manually controlled. Instead, CNC (Computer Numerical Control) machines such as vertical mills are used to manufacture parts, molds and/or EDM electrodes in accordance with a set of CNC instructions. To compute detailed toolpaths for the tools assigned by the moldmaker or machinist and to produce long sequences of such instructions for CNC mills, CAM (Computer-Aided Manufacturing) software can be used. CAD/CAM software packages are built around geometry kernels—computationally intensive software implementing numerical algorithms to solve a broad set of mathematical problems associated with analysis of geometrical and topological properties of three-dimensional (3D) objects, such as faces and edges of 3D bodies, as well as with generation of new, derivative 3D objects. At present, a number of mature and powerful geometry kernels are commercially available.
In recent years, computer-based communications regarding custom parts has become more and more commonplace. Often part designers do not even meet face-to-face with the machinist or company that will manufacture a custom part. Instead communications occur over the internet, including transmission from the part designer of a CAD file representing the design of the part, and a computer-based quotation from the manufacturer of the cost of custom manufacturing of the part. Examples of such computer-based communication and quotations systems are those provided by Proto Labs, Inc. and detailed in the following patents and patent applications owned by Proto Labs, Inc. and all incorporated by reference:                U.S. Pat. No. 6,701,200, entitled Automated Custom Mold Manufacture;        U.S. Pat. No. 6,836,699, entitled Automated Quoting of Molds and Molded Parts;        U.S. Pat. No. 7,089,082, entitled Automated Multi-Customer Molding        U.S. Pat. No. 7,123,986, entitled Family Molding;        U.S. Pat. No. 7,299,101, entitled Manipulatable Model For Communicating Manufacturing Issues Of A Custom Part;        U.S. Pat. No. 7,496,528, entitled Automated Quoting of Molds and Molded Parts;        U.S. Pat. No. 7,574,339, entitled Automated Generation Of Lean Models For Injection Molding Simulation;        U.S. patent application Ser. No. 10/970,130, entitled Automated Quoting of Molds and Molded Parts;        U.S. patent application Ser. No. 11/338,052, entitled Communicating Mold/Part Manufacturability Issues;        U.S. patent application Ser. No. 11/368,590, entitled Graphical User Interface For Three-Dimensional Manipulation Of A Part;        U.S. patent application Ser. No. 11/586,223, entitled Automated Total Profile Machining of Parts;        U.S. patent application Ser. No. 11/586,379, entitled Automated Quoting Of CNC Machined Custom Molds And/Or Custom Parts;        U.S. patent application Ser. No. 12/136,552, entitled CNC Instructions For Solidification Fixturing Of Parts; and        U.S. patent application Ser. No. 12/354,546, entitled Automated Quoting of Molds and Molded Parts.These computer-based improvements have collectively both streamlined and added flexibility to the custom part design/quotation/manufacture process.        
At the same time as all these computer advances, however, part designers commonly have less and less engineering knowledge and experience. When custom parts interact with the real world, real world constraints and standards may or may not be known to the part designer.
One increasingly prevalent example occurs when a custom part is intended to be assembled with or otherwise mate with a threaded fastener. While the part designer may desire a custom part, the part designer may have no desire or purpose for using a custom threaded fastener. Instead, the part designer may want to use the most inexpensive fastener that will work for the attachment function. Standards have been developed and published for threaded fasteners, including ANSI/English (American National Standards Institute) and ISO/metric (International Organization for Standardization) classifications. See ANSI/ASME standards B1.1, B1.10M, B1.13M and B1.15 and ISO standards 68-1, 68-2,261, 262 and 965 et seq. These standards detail hundreds or thousands of different thread sizes, fit and tolerance values.
These standards are unknown to many part designers, and are not well understood by other part designers who are aware of the standards. Further, some of the standards define more common fasteners, while other standards define less common fasteners, and most part designers have no easy reference to discern which is which. In some cases, a part designer who simply desires a tapped hole for a “common” screw size may unintentionally specify an uncommon screw size or tap. The unintentional uncommon specification may occur either in detailed CAD drawings for the screw threads of the tapped hole, or through specifying an uncommon standard. In many more cases, the part designer may not specify any tap or screw size, and instead perform the drilling and/or tapping operation separately after the custom-designed part has been delivered by the manufacturer. In other words, often times the difficulty in identifying and communicating the desired screw thread parameters over the internet leads many part designers to adopt an “We'll just take care of that aspect later by ourselves” approach.
Even if the designer knows how to specify a desired thread size, there is no standard way to annotate 3D-CAD drawings with thread information. Several of the common 3D-CAD packages don't even have a non-standard way to add thread annotations or meta-data.
Even if the thread size is properly specified, the part designer may not know which size pilot hole to use for the tap. Various published references provide different recommendations for pilot hole sizes, and the part designer may not know which size to use. For instance, for tapping a #2-56 UNC 2B ANSI thread, different references might recommend either a #49, a #50, or a #51 pilot hole. The recommended pilot hole size may also depend upon the amount of thread forming performed by the particular tap, which is not commonly known by the part designer. The recommended pilot hole size may also depend upon the depth of the threaded portion of the hole, using relationships not commonly known to the part designer.
Many part designers do not have the time or inclination to become experts in screw threads. Better systems, which are simpler from the customer's perspective, need to be developed.